Interpretation of the cosmic ray positron and antiproton fluxes

Abstract

The spectral shape of cosmic ray positrons and antiprotons has been accurately measured in the broad kinetic energy range 1-350 GeV. In the higher part of this range (E > 30 GeV) the e+ and pbar are both well described by power laws with spectral indices gamma[e+] = 2.77 +-0.02 and gamma[pbar] = 2.78 +- 0.04 that are approximately equal to each other and to the spectral index of protons. In the same energy range the positron/antiproton flux ratio has the approximately constant value 2.04+-0.04, that is consistent with being equal to the ratio e_/pbar calculated for the conventional mechanism of production, where the antiparticles are created as secondaries in the inelastic interactions of primary cosmic rays with interstellar gas. The positron/antiproton ratio at lower energy is significantly higher (reaching the approximate value e+/pbar = 100 for E around 1 GeV), but in the entire energy range 1-350 GeV, the flux ratio is consistent with being equal to ratio of the production rates in the conventional mechanism, as the production of low energy antiprotons is kinematically suppressed in collisions with a target at rest. These results strongly suggest that cosmic ray positrons and antiprotons have a common origin as secondaries in hadronic interactions. This conclusion has broad implications for the astrophysics of cosmic rays in the Galaxy.

Rextex 23 pages 9 figures. Paper replaced to match with version accepted in Phys.Rev.D. Included more critical discussion and relevant citations

References in corpus (13)

• PYTHIA 6.4 Physics and Manual
• Observation of an anomalous positron abundance in the cosmic radiation
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• Discrepant hardening observed in cosmic-ray elemental spectra
• The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
• Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight
• Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data
• Flavor Composition and Energy Spectrum of Astrophysical Neutrinos
• Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment
• Measurement of boron and carbon fluxes in cosmic rays with the PAMELA experiment
• Solution to the cosmic ray anisotropy problem
• Observations of the Li, Be, and B isotopes and constraints on cosmic-ray propagation
• The boron-to-carbon abundance ratio and Galactic propagation of cosmic radiation

Cited by in corpus (21)

• Galactic cosmic rays after the AMS-02 observations
• AMS-02 beryllium data and its implication for cosmic ray transport
• Galactic factories of cosmic-ray electrons and positrons
• Gamma-ray halos around pulsars as the key to understanding cosmic ray transport in the Galaxy
• Diffuse γ-ray emission from self-confined cosmic rays around Galactic sources
• Signature of Energy Losses on the Cosmic Ray Electron Spectrum
• On particle acceleration and transport in plasmas in the Galaxy: theory and observations
• On the spectrum of stable secondary nuclei in cosmic rays
• Where are Milky Way's Hadronic PeVatrons?
• Effects of reacceleration and source grammage on secondary cosmic rays spectra
• Millisecond Pulsars Modify the Radio-SFR Correlation in Quiescent Galaxies
• Implications of a possible TeV break in the cosmic-ray electron and positron flux
• Nonsecondary origin of cosmic ray positrons
• On the origin of the spectral features observed in the cosmic ray spectrum
• Examining the secondary product origin of cosmic ray positrons with the latest AMS-02 data
• Regions of suppressed diffusion around supernova remnants?
• Direct measurements of cosmic rays and their possible interpretations
• Deflection of charged massive particles by a four-dimensional charged Einstein-Gauss-Bonnet black hole
• Deciphering the Electron Spectral Hardening in AMS-02
• Non-linear Cosmic Ray Propagation
• The self-control of Cosmic Rays